Ecosync

The expression "money doesn't grow on trees" has a particular ring
of truth to electrical utilities. Even the reverse statement that trees grow on
money might seem apropos.

Senior management of TransAlta Utilities Corporation (TAU) Calgary, Alberta
was highly dissatisfied with the fact that eventhough the distribution line
clearance budget had been increased an average 35% a year between 1978 and 1984
there were few if any discernible positive results.

Tree related power outages kept increasing. Complaints and claims against the
company were increasing. Lawsuits both for removing trees and not removing
enough trees resulting in personal injury accidents were pending. The budget
requests from the field indicated a continuation of this sharply upward trend.
Was the field staff right? Would further increases produce results?

This line of questioning ultimately led to the question, what is the right
amount of funding? This question was pivotal, because in searching for the
answer TransAlta was exposed to the concept that the right level of funding can
only be determined through an inventory of tree work. This inventory is
comprised of basically two factors, the number of trees in proximity to the
power lines and the local growth rates.

The value of a tree work inventory is often questioned. One argument is, why
spend money counting trees instead of cutting them? Consider this analogy. If
you were asked to resolve a flooding problem on a river what are the chances of
doing so, if the budget is set but you do not have the width, seasonal flow
rates, geological data nor are you permitted to spend any money gathering this
information because it would reduce the amount of concrete you could purchase?

TAU hired a consultant to do the inventory. Based on the inventory the
consultant made a 12 year budget projection. The period covered entailed a 6
year 1st cycle or catch up phase and a 6 year 2nd cycle maintenance phase. The
1st cycle budget was a significant increase over the existing budget. TAU chose
to extend the 1st cycle over an eight year period to more effectively use
experienced contractor staff. For the maintenance phase the budget was forecast
to drop back to and be sustained at the 1985 level.

In implementing the new vegetation management program in 1986 TAU decided to
contact each landowner directly to obtain consent to undertake the tree work.
The intent was to reduce the risk of claims while maximizing tree removals.
Complaints and claims were dramatically reduced and currently run at about 1
per 1000 landowners. Upon completion of the field work 5% of the landowners are
randomly sampled with a door tag survey. The return rate is over 25% of the
tags with 98% rating their experience with the vegetation management work as
satisfactory or better (1992 and 1993).

Customers place a high value on reliable service. In a 1993 survey, TAU
customers were asked to rate twenty service factors in terms of importance and
how they perceived TAU's performance on each of these. Reliability topped the
list in importance at 99% while TAU's delivery of reliable service was rated at
94%. Other factors ranked included restoration of service, operating
efficiency, courteous employees, satisfying customer needs, rates and
environmental performance. One would expect little elasticity in the customers'
demand for reliability. After all, courteous employees or low rates cannot
compensate for a lack of the basic commodity, electricity, the customer
believes to have purchased. In fact, one might speculate that service
interruptions may lead customers to feel that they are paying too much for what
is perceived to be a poor service.

Public safety is the other side of the coin of reliability. While trees
falling on a power line may cause a service interruption, each such contact
carries with it the risk that some person may be exposed to an electrical
hazard either by contact with the tree or downed power lines. Utilities face a
considerable liability given that court rulings appear to indicate that the
public cannot be expected to recognize electrical hazards and thus electric
utilities being cognizant of, and introducing the hazard must act with due
diligence to protect the public.

The risks presented by trees within striking distance of a power line, can
be minimized. Success requires a budget based on long term thinking, an
accurate assessment of all the work required and the courage to remain
committed to the plan. Remaining committed to the plan is important because
results will not be immediate. Generally, as in TAU's case, it would not be
practical to do all required vegetation management work in one year. Dealing
with vegetation one is faced literally, with a growing not static system. Tree
caused outages did not start to decrease until the third year. Since then
though, there has been a dramatic 80% drop. TAU's tree related outages were
close to the Canadian average of 15% in 1985. In 1992 tree related outages were
only 3% of the total.

Outages were caused predominantly by trees falling on the line. Recognizing
this and the higher costs associated with repetitive trimming, TAU focused on
getting tree removals. During the 1st cycle 75% of all the trees handled were
removed. The high tree removal rate is attributed to the decision to meet each
landowner face to face to gain consent. Although, consenting is a substantial
cost, the idea to empower the landowner by providing information regarding the
vegetation management costs and objectives led to a level of cooperation that
far exceeded expectations. The benefit of removing trees which otherwise would
have to be trimmed offset the cost of obtaining consent.

Outages resulting from the regrowth of trimmed trees are being minimized by
an appropriate trim cycle. TAU trim cycles are based on the clearance obtained
when trimming and growth rates. While nature sets the growth rate, it can be
heavily influenced by the quality of trimming. Improper pruning practises such
as stubbing or removal of large portions of the crown often triple the rate of
regrowth. The clearance obtained is affected by customer contact policies, the
target clearance and customer desires. TAU has set a target clearance of 4.5
metres (15') for trimming. After customer input the average clearance actually
obtained is 3 metres (10').

TAU invested money to decrease the tree liability but the budgets have
dropped back to the 1985 levels as predicted for the maintenance phase. Nature
and landowners keep planting trees near power lines. Trees mature becoming
susceptible to disease. While trees have many environmental and aesthetic
benefits, financially, tall maturing trees are an expanding liability to
electric utilities. Though utilities routinely use long term planning for
assets such as generation facilities, it's a shift to apply the same thinking
to a liability such as managing vegetation. Just as utilities can't rationalize
a generation facility based on just one year of operation, they can't manage
vegetation on a one year plan. But by making a long term plan based on an
actual tree work inventory TAU's success can be replicated.

Sig Guggenmoos is the Senior Consulting Forester for TransAlta Utilities
Corporation's Forestry group. He holds a Bachelor of Science in Agriculture
degree from the University of Guelph, Guelph, Ontario where he majored in horticulture.